Single Phase Full Wave Controlled Rectifier with R Load

The circuit consist of four thyristors T1, T2, T3 and T4, a voltage source Vs and a R Load.

The circuit consist of four thyristors T1, T2, T3 and T4, a voltage source Vs and a R
Load.
 During the positive half cycle of the input voltage, the thyristors T1 & T2 is forward
biased but it does not conduct until a gate signal is applied to it.
 When a gate pulse is given to the thyristors T1 & T2 at ωt = α, it gets turned ON and
begins to conduct.
 When the T1 & T2 is ON, the input voltage is applied to the load through the path Vs-
T1-Load-T2-Vs.
 During the negative half cycle, T3 & T4 is forward biased, the thyristor T1 & T2 gets
reverse biased and turns OFF
 When a gate pulse is given to the thyristor T3 & T4 at ωt = π+α, it gets turned ON and
begins to conduct.
 When T3 & T4 is ON, the input voltage is applied to the load Vs-T3-Load-T4-Vs.
 Here the load receives voltage during both the half cycles.
 The average value of output voltage can be varied by varying the firing angle α.
 The waveform shows the plot of input voltage, gate current, output voltage, output
current and voltage across thyristor.